Bandai B-Train Shorty - Bended axle?

[Dinosbacsi]

By the way, hopefully I'm not getting annoying with all my questions, but I have some regarding the way my Bandai power unit runs.

 

Long story short, it runs pretty good, but it gets a bit jittery at slower speeds. I tend to run it on 3rd or 4th "notch" (or whatever I should call the little markers on the controller), so around quarter speed, and it does slow down from time to time and very rarely it even stops and I need to push it to get it started again. Also if I apply power too slowly from a stand still, it sometimes won't move and I need to push it to get it started. So basically, is this normal?

 

On the side note, this jittering and stopping seems to be worse when it's in reverse. It runs much smoother when it's running forwards. At first I tought maybe it's because it's the 3 car in the consist when in reverse, compared to being only the second one while going forward, but I tested it running alone and it behaves similarly.

 

I also noticed that one wheel of the power unit seems to be out of alignment or something, as it's not centered properly, therefore makes the whole powered car jump up and down a bit as it rotates, especially if this wheel is at the front. Could this "loose" wheel cause some of the jittering and stopping, by lifting the car and it not getting enough contact with the rails?

[lukewang01]

Is the power unit new or used? I've had this problem on used ones, and I'm waiting on my HS order that has some hobby grease and switch lubricant. I'll report back if they improve power unit's running conditions. 

As to the out of alignment issue, I haven't come across that yet. 

[Dinosbacsi]

It was new, with the whole box still in plastic packaging.

 

Since then I tested it a bit more, tried adding the 4 weights that were included, but that actually just made it run worse, lol. So I'm starting to think that the wobbly wheel is the issue. Adding the weight probably made the wobbly wheel either not make contact with the rail or with the pickup plate thingies inside the bogeys?

It runs a bit better with the 3 other cars attached than alone, I suppose the other 3 car's help get it over the small pauses, so I wonder if adding weights to the other cars instead would make it run better.

 

As for the out of alignment/wobbly wheel, is it possible that the axle is bent a bit or something? Should I take it apart maybe? From what I can see, it's just the matter of two screws and popping the electric motor off?

[disturbman]

That's my question is the wheel not properly slotted inside the notch in the bogie/truck? It could have been dislodged by a shock during transport. A bended axle should be pretty rare... hopefully. I am only backseating as I never had a banda power chassis. Pictures could be helpful.

Edit: I see. You probably need to take everything appart to see what's wrong inside the bogie.

http://rtmrw.parallel.jp/engineering1/eng-report11/eng-report11.html

"I'm a little dissatisfied with the coupler replacement. The chassis interferes with the coupler and cannot be easily removed. The dolly can be disassembled, but it is not easy to remove the dolly because it cannot be removed without disassembling the entire dolly. Therefore, it was necessary to have a brute force in anticipation of bending of the interference part. After the disassembly investigation, I replaced it with Kato Coupler N as usual."

Edited March 22, 2021 by disturbman

[Dinosbacsi]

I uploaded a video, as it probably shows the issue better than words or pictures. It looks to me like it's the second axle from the left that causes wobbling.

 

I also wonder if it kept stopping because of loss of electric contact or simply because of friction and not being able to go.

[Dinosbacsi]

20 hours ago, disturbman said:

That's my question is the wheel not properly slotted inside the notch in the bogie/truck? It could have been dislodged by a shock during transport. A bended axle should be pretty rare... hopefully. I am only backseating as I never had a banda power chassis. Pictures could be helpful.

Edit: I see. You probably need to take everything appart to see what's wrong inside the bogie.

Well going by the pictures in the website you linked, it's not that complicated of a mechanism so hopefully it's easy to take apart and put back together, so maybe I'll try that sometimes. For now it's not that bad, it goes pretty okay around the triangular loop I made on my desk, but I'll see how it will handle the junctions I ordered when they arrive. If it handles junctions and curves going the other way worse, then I'll definitely take it apart for a check.

[disturbman]

It seems worth the effort. Even more if it’s not bended but just popped out. At least it’s not the axle with the rubber, but it shouldn’t be like that.

[Dinosbacsi]

Yeah I read that these are two half axles popped into a middle piece? So it's a possibility that one is just not pushed in properly?

(By the way thanks for moving the thread)

[disturbman]

That's a very strange configuration but, yes, there is always a possibility that something is not pushed in properly. Or that something could have gotten loose/dislodged in transit.

I recently received a set that spent a long-time on the road, and almost all the air-conditioning units and a power bogie had come loose.

[Dinosbacsi]

Well, I got to removing the bogey that has the wobbly wheel, and it looked like the outer axle did have quite a wobble indeed. Though I'm not sure if it's the axle being bent or just the wheel not being completely straight on the end of the axle. I don't know how to take the bogey itself apart, so I can't inspect just the axle itself.

 

But anyway, can these (either the wheels or the axle itself) even be bent by hand? Because I tried pushing it and such and for a while it looked like I bent it even more and made it worse. Then I tried some more and in the end I might have made it a bit better?  But I'm not sure. It's hard to tell when it's really better or worse.

 

I tried rotating the wheels by hand and pushing the bogey on the track by my finger and it looks like it's a bit better than it was before. So it it possible I straightened it out a bit my pushing the two wheels from the two sides? I mean I don't think it should bend this easily, but I don't know.

[disturbman]

I would not try to remedy the issue without opening the bogie first. You could make the issue worst or break something. Japanese internet might have more info on how to open these. Maybe @cteno4has an idea on how to proceed?

[cteno4]

Sorry ive never torn apart a bandai mech before, I only have a couple of the bandai. I’ll pull one out and take a quick look at it to see if it looks simple to pull apart. I’m kinda hesitant to just pull one working fine apart just to figure out how they disassemble as I’m kind of guessing these inexpensive mechs were designed for rapid assembly one way and not a graceful disassembly for working on them. I think I know where one of the mechs is I may not have used yet.

 

generally trucks usually have an inner core that holds the gear and then an outer frame that pops on around the inner frame. Usually you pop it off at the ends of the trucks prying out a finger from the outer frame that slots into the inner piece to hold the frame in place.

 

i agree something like this will require disassembly of the truck so you cna determine exactly what is off with the wheel sets wobbling and attempt fixing it.

 

jeff

[Dinosbacsi]

Yeah I suppose it's a simple pop-together-the-two-pieces frame, considering pretty much the whole Shorty structure is built that way. Even the bogeys themselves come off easily just by rotating them 90 degrees. But I just couldn't find where they actually separate and where I should try taking it apart.

[disturbman]

@cteno4No worries, I only summoned you as I know you have good technical knowledge, and because I thought you might have had to open one or something similar in the past, not to make you disassemble one 🙂

Edited March 25, 2021 by disturbman

[cteno4]

Unfortunately we have not had a lot of btrains here in the club and vast majority of mine are Kato pocket mechs. I think I know which unmade set I stashed the bandai mech in its box as there was something someone said about the mech working better with that train and I only had a couple of the bandai mechs. One is in one of my sets already but I have no idea which one!

 

jeff

[Dinosbacsi]

Well good news is, I managed to take the bogey apart. As expected, it just uses 3 pins to pop together, 2 at the sides on the coupler end, and 1 bigger on the non-coupler end.

 

Bad news it, I still don't exactly now what the issue is?

One thing I noticed is the gaps between the middle cog bits and the wheel bits. Do you guys think that's normal?

 

And it's really hard to tell, but maybe the left axle is bent? Or the wheel, I don't know, but the flanges definitely don't seem to meet up on the top. And the left one seems to bit a bit wonky, judging by this picture.

 

I tried experiementing with the wheels themselves, slowly raising one end of a straight track and see how well they roll. Interestingly, they seemed to roll well and I if I saw any wobbles, it was barely noticeable with the naked eye. Yet when the whole set is assembled, it wobbles to the point where the axle sometimes even gets stuck and stops rolling (which I suppose may be the reason for the train stopping sometimes and running harder as well). I also can't decide if it's the axle or the wheel being bent, or if it's the middle cog bit that's uneved and causes it.

 

What do you guys think? Are those gaps normal? I don't think they are, as I placed them besides other bogeys and their gauge seem to be a bit longer, maybe even by a whole 1mm. How do you fix this? Just push on the wheels from two sides?

And if the axle really is bent, can that be adjusted somehow? Similarly just try to apply some force on it?

 

Edit: Of course I can't be totally sure, but I think it is the axle being a bit bent, and it looks like it can be also bent by hand a bit. So should I go for it and try straigheting it with hand? Or would pushing the wheels in, as said, probably straighet the axle as well?

Edited March 29, 2021 by Dinosbacsi

[cteno4]

Ahh good info! Hard to tell if bent in the photos and parallax and angle could exaggerate that visually. Rolling then on the table should show some wobble if bent.

 

So it looks like there is a little half axle on each wheel that fits into the sleeve axle on the gear. If these seem too wid a gauge that could be causing the issue in the truck with the other gears not having enough play. Do you have a Kato unijoiner puller/clearance gauge? They have a flange gauge at one end that shows proper gauge. You could try to push them back in to see if you can get it to the correct gauge. My guess would be that the fatter bit of the metal wheel axle should butt up agains the plastic collar of the gear axle, but that looks like it might be too much. The one wheel set seems to be butt up against in one side and the other side more even. I wonder if regauging to make sure it’s proper n gauge and trying to get the gear evenly spaced might make it then run more evenly. 
 

jeff

[Dinosbacsi]

Yeah, I tried rolling them both on the table surface and on a piece of straight rail as well. I think I saw some wobble in the axle.

 

But what I also discovered is that for both bogeys, when they are being pushed towards their couper end, there often seems to be pretty violent shaking in the axles or something. So basically they run smoother when they are rolling towards their non-coupler end, but when rolling towards their coupler-end, the axles seem to "dance" quite a bit, I think it might be something to do with how the cogs are pushing each other differently to one direction, compared to when going the other way. And this "dancing" also seems to result in the wheels grinding against the pickup plates more than they probably should, they keep lifting them up and down, and often you can hear the inside of the wheels scraping them, and the wheels sometimes even get stuck because if this. It also seems to be worse in curves.

 

I don't know what is and what isn't normal out of all this, I mean maybe the wheels lifting the pickup plates a bit is normal etc, I don't know. But I guessed I should share what I found. I'm also starting to think that maybe all 4 axles are bent a bit, not just one? Because both bogeys seem to have a very slight up and down movement as they roll. But it's quite small, I don't know if it should be enough to result in such problems.

 

A question, just for comparison, the bogeys from the powered chassis should run as smoothly as the ones from the non-powered ones? Because those run really smoothly, not a single unevennes in their ride. if the powered chassis bogeys are supposed to be the same as well, then something is really wrong with mine, lol. I hope I can get a second one in the near future to see how it runs for comparison.

[cteno4]

I’ll try to get to mine to tonight, which number unit is it?

 

if the gauging is not right and gear not quite in the right place along with the pickup action it could be a complex interaction that ends up in it wobbling. Might try pulling the wheels out of the center plastic axle on the one you think looks out of line and make sure there is nothing in the hole like some flashing or something. If something is bent I think it’s the center plastic axle/gear and the wheel axles just not going into the center gear/axle nice and straight. Once removed you can check the wheel axles are square with the wheels by rolling it along a nice square edge with the wheel flush onto the corner and if the axle is not square into the wheel you will see gaps with the axle and surface come and go as your roll it along the edge.

 

jeff

[Dinosbacsi]

Thanks, that would be great. It's a power unit 3.

 

Though I don't know what I just did, because I put it back together and now it barely wants to run... There doesn't seem to be contact or something, even though the pickup plates are in their place and so is everything else. It needs a lot of pushing around for it to get contact and start going. Is it possible that's it's just dirt or grease from my hand getting on the end of the contact plates and therefore a bad contact, or that's not something that usually happens (and therefore I probably messed something else up)?

 

I suppose I will try to see if I can take apart the axles tomorrow. By the way are there replacement axles for these anywhere? I know Kato makes replacement axles for their free rolling bogeys, but are these any cogged axles that fit into these Bandai units?

[cteno4]

Probably not from your fingers, the wheels did look like they had a fair amount of dirt on them, you may have reassembles with the worst wheels all on one side! 
 

I doubt there are any spare parts. Bandai isn’t really a train manufacturer like Kato where you can get spare parts. Even then I’m not sure if Kato even sells spare parts for the pocket mechs.

 

jeff

[lukewang01]

Have you checked contact points between copper strips and the motor itself? It could be out of place during reassemble and cause bad contacts. 

[cteno4]

Ok, I pulled mine apart, pretty standard design, but fiddly and tiny. 
 

what I found is my metal wheel axles are pushed full up against the plastic center gear axles. I suspect your problem is they were not pushed all the way into the center plastic axle and thus maybe off kilter a bit and also the  cause binding on the pickups and gear meshing.

 

if you have some calipers, my flange gauge inside the flanges is about 7.40mm

 

mine was also bone dry on lubrication. I finally broke down and ordered some nano lube last week and this will be my first loco to try it on, mine runs like it’s a bit dry on lube.

 

on the issue of funky contact it could be the long chassis pickup strip. One of them (the side that doesn’t pickup the capacitor wire) would not stay in place well on its own each time I went to snap on the top motor/casing. I ended up putting a little dot of fabric glue (it’s basically a thick rubber cement) under the strip so it would say in place during the final snap of the top chasis.

 

cheers,

 

jeff

[Dinosbacsi]

Thanks for the photo, Jeff. After struggling for more than a hour at night before bed, today I managed to fix it before work in under 30 minutes. Pushed the wheel in properly on all 4 axles, and it really did improve things drastically! The axle with the traction wheel was still a tiny bit bent though, but managed to straighten it out as well, so now it runs so much better.

 

The up-down bouncing while running is completely gone, it does slow speed crawling significantly better and it also handles turnout good now! There is still some slight jittering in speed while going through curves, and slowing down in them in general, but nothing too bad. But I'll check and see if turning any of the contact plates inside the bogeys around will help it, as I noticed that they're not entirely straight, so depending on how you put them in, they may rub to the inside of the wheels differently.

 

And just as you said, my one is also pretty much completely dry on the inside, so I'll probably try some lubrication as well. Is there a specific brand that's good for them, or will any model train stuff do? Because if so, then I'm not going to bother ordering one from Japan, I'll get one locally. Or I even have some spare motor oil or transmission oil left around at home, if that works, lol?

 

But anyway thanks for the help guys, the poor performance really started to bother me, it's so nice to see it running better. If some lubrication improves it even further, then I'm going to be completely satisfied, but this is already great improvement.

[cteno4]

Yayyyy! Always love it when this is the outcome! Nice feeling of satisfaction for you having dived in and opened it all up and now found the fix!
 

on the truck pickups mine looked pretty flat, the only side difference on them I noticed was one side had rounded edges and one side had sharper edges Im guess due to the stamping of the part so I put the rounded sides facing out toward the back of the wheels.
 

usually on gears I use a medium weight oil like labelles 102, but for these I may try something a little lighter and less gummy as the gears and wheels are very loose in there and lightweight. I finally ordered some nano lube (it’s carbon buckyballs in a penetrating oil) to try for stuff like this. It’s meant to use the buckyballs as the eventual lubricant and meant for smaller fiddly things that only very light oils would work well on but tend to not stick around. Also hope it’s less of a schmutz attractant. We shall see. It’s expensive but should last! Apply the oil a tiny bit at a time. add some then run for a few laps and then repeat as needed. If you listen closely you will hear a point which things go from more of a grind to a purr, stop then.
 

You can use a tooth pick or a little easier is the eye end of a sewing needle. Just stick a sewing into a chopstick end and it makes a nice applicator as the eye holds a bit of oil but doesn’t release it all in a blip the way a drop on the end if a toothpick can. I mainly use the dental cement applicators. They are sort of like tiny swabs and very handy at dabbing on the oil as you want. 

 

https://www.ebay.com/itm/100-Pcs-Dental-Disposable-Micro-Brush-Tooth-Applicator-Tips-Sticks-1-2mm-White/283312944456?hash=item41f6c47548:g:TE8AAOSwVRBcHe44
 

if you’re in the us I can easily toss a few of these and a little bit of the nano oil into the mail for you. Unfortunately shipping outside the us gets hideously priced fast then sets off the customs bells in many places for a few cents of stuff...

 

cheers

 

jeff